Without limiting the scope of the invention, its background is described in connection with single stranded DNA aptamers and their therapeutic and diagnostic applications.
U.S. Patent Application No. 20080261225 (Ahn and Yang, 2008) discloses a method and a kit for detecting a target protein in a sample with a signal amplification strategy are provided. The signal amplification strategy is established for the aptamer-based molecular recognition of a target protein with concomitant release of single-stranded DNA (G-DNA), which binds complimentarily to a single-stranded RNA comprising a fluorophore and a quencher (“F-RNA-Q”). The fluorescence-quenched RNA is then degraded by RNase H to result in a fluorescence signal, and the undamaged G-DNA is recycled to yield fluorescence amplification.
U.S. Pat. No. 6,867,289 issued to Gorenstein et al. (2005) relates the generation of aptamers and to the use of aptamers as diagnostic and therapeutic agents. More particularly, the Gorenstein invention relates to methods using combinatorial chemistry to prepare aptamers having controlled thiophosphate replacement in the phosphate backbone for improved binding efficiencies to a target and to RNA and/or DNA products having novel nucleotide sequences and enhanced target binding efficacies.
U.S. Pat. No. 7,309,786 issued to Zhang et al. (2007) relates to a group of new oligonucleotides sequences with human tumor necrosis factor α (TNF-α) inhibiting activity, which includes DNA sequences and RNA sequences. These oligonucleotides or aptamer can specifically be bound to TNF-α and inhibit the cytoxicity of TNF-α to L929 cells. The aptamers taught by Zhang can be used to detect TNF-α and provide a therapeutic method for diseases related to the increasing level of TNF-α. Compared with other TNF antagonists such as monoclonal antibody and soluble receptor. The aptamers by Zhang are also said to have high specificity, high affinity, quick penetration to target tissue, rapid plasma clearance, and lower immunogenicity. Furthermore, it can be used repeatedly and keeps high concentration in target tissue and the like. It has the advantages of affinity and specificity similar to monoclonal antibodies and also has permeability and pharmacokinetics characteristics similar to small molecular polypeptide. Zhang also refers to derivative of the oligonucleotides sequence, including modified sequence. Finally, the aptamers taught by Zhang may further be manufactured as medicine for therapy and diagnosis of TNF-α related diseases.